Iron carbonyl complexes of azo compounds

ABSTRACT

A DIIRON HEXACARBONYL COMPLEX OF BENZO (C) CINNOLINE IS PROVIDED WHICH HAS THE FORMULA   R,R1-BENZO(C)CINNOLINE.2FE(CO)3   WHEREIN R AND R1 ARE HYDROGEN, METHYL OR HALOGEN. IN ADDITION, A METHOD FOR PREPARING SUCH COMPLEXES IS PROVIDED WHICH COMPRISES REACTING A BENZO (C)CINNOLINE WITH AN IRON CARBONYL AT A TEMPERATURE ABOVE ABOUT 100* C. IN WHICH THE MOLAR RATIO OF BENZO (C)CINNOLINE TO CARBONYL IS FROM ABOUT 1:1 TO 3:2.

U-S. Cl. 260-242 Int. Cl. C07d 51/10 a 3 Claims ABSTRACT OF THE DISCLOSURE A diiron hexacarbonyl complex of benzo(c)cinnoline is provided which has the formula I R R1 \NN:

' (CO) Fe Fewo wherein R and R are hydrogen, methyl or halogen. In addition, a method for preparing such complexes is provided which comprises reacting a benzo(c)cinnoline with an iron carbonyl at a temperature above about 100 C.

in which the molar ratio of benzo(c)cinnoline to carbonyl is from about 1:1 to 3 :2.

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of US. Patent Application Ser. 'No. 154,668 filed June 18, 1971, now abandoned, which in turn is a continuation-in-part of US. .Patent Application Ser. No. 775,188, filed on Nov. 12, 1968, now abandoned.

This invention relates to iron complexes of azo compounds. More particularly, this invention relates to iron carbonyl complexes of azo compounds, their method of preparation and to substituted phosphine, arsine and stibine derivatives of the iron carbonyl complexes.

BACKGROUND OF THE INVENTION Attempts have been made in the past to prepare iron carbonyl complexes of azo compounds, particularly by employing photolytically promoted reactions of an azo 'compound with an iron carbonyl compound. Thus, when azobenzene was reacted with an iron carbonyl, the product was found to be a complex of o-semidine rather than iron carbonyl complex of azobenzene.

THE INVENTION The present invention is based on the discovery that iron carbonyl complexes of aromatic azo compounds can be successfully formed by heating an azo compound with an iron carbonyl compound at elevated temperatures above 100 C. The reaction can be carried out either in the absence or presence of a solvent. It is preferred to carry out the reaction in an inert solvent in which both the starting materials and the product are soluble, such as decalin. The reaction temperature employed is that which effects the desired reaction without degrading a significant portion of the product. Thus, it is preferred to employ reaction temperatures in the range of from 110 C. to 170 C. The elevated temperatures are maintained until evolution of carbon monoxide gas substantially ceases. The product is then recovered by removing the United States Patent Patented Aug. 20, 1974 "ice mula:

(COM M M wherein R and R are hydrogen, methyl or halogen.

The members of this new class of compounds are useful as initiators and promotors for the polymerization of certain monomers such as styrene and methyl methacrylate and, in addition, as anti-knock additives for gasoline. They are also useful as oxidation catalysts to promote the burning of fuel oils.

Any aliphatic or cyclic, cis or trans, azo compound can be reacted to prepare the complexes of this invention. The azo compound can be a non-azo or poly-azo compound. Illustrative azo compounds which may be used include compounds such as benzo(c)cinnoline and derivatives thereof including monoor polyhalo-benzo(c)cinnoline, and polymethyl-benzo(c)cinnoline.

The iron carbonyls useful in forming the complexes are iron pentacarbonyl (Fe(CO) diiron nonacarbonyl and triiron dodecacarbonyl (Fe (CO) The ratio of iron carbonyl reactant to azo reactant depends on (1) the iron carbonyl reactant employed and (2) the number of azo groups in the azo reactant to be complexed. For any given azo reactant the product is the same for all three iron carbonyl reactants. For each azo group complexed, the product contains a a (CO)3F8 moo):

Generally, the use of about 10% excess of iron carbonyl reactant insures relatively complete reaction of the azo compound. When it is desiredto partially complex the poly-azo compounds, at least sufficient iron carbonyl is Benzo(c)cinnoline (13.92 g., 0.077 mole) and iron pentacarbonyl (32 g., 0.163 mole) were mixed in decalin (125 ml.) and heated at 150 C. until gas evolution ceased. The reaction mixture was cooled and then filtered and the filtrate chromatographed on alumina. The solvent was removed with petroleum ether and the product eluted with petroleum ether/benzene (4/1) which, on evaporation, yielded 28.25 g. (79% yield) benzo(c)cinnoline diiron hexacarbonyl, red crystals, m.p. 153-5 (dec.).

The complex which has the following structural formula:

(COMFAFHOO);

is non-conducting in nitromethane; mass spectrometry shows 6 carbonyl groups; ceric ammonium nitrate decomposes the complex to give a quantitative yield of benzocinnoline.

EXAMPLE 2 Using the procedure of Example 1 and the appropriately corresponding starting materials, the following iron carbonyl complexes were prepared.

1,10-Dichlorobenzo (c)cinnoline diiron hexacarbonyl 3,8-Dichlorobenzo(c)cinnoline diiron hexacarbonyl (CO)3F L Fe(CO);

EXAMPLE 3 Preparation of Benzo(c) cinnoline diiron pentacarbonyl triphenyl Phosphine Benzo(c)cinnoline diiron hexacarbonyl (1.0 g., 0.0022 mole) and triphenylphosphine (0.57 g., 0.0022 mole) in benzene (50 ml.) were heated for about /2 hour with stirring until gas evolution ceased. The reaction mixture 3,830,807 I y p H was cooled and evaporated to dryness. The remaining solid was triturated with petroleum ether followed -by warm ethanol to remove unreacted starting materials. The resulting solid was then dried, wt. 1.5 g. (100% yield), m.p. 205 (dec.).

EXAMPLE 4 EXAMPLE 5 METAL CARBONYL COMPLEX AS POLYMERIZA- TION INITIATOR Two test tubes were prepared with 2 ml. of inhibitorfree styrene in each. To one test tube was added 10 milligrams of benzo(c)cinnoline diiron hexacarbonyl while the other sample was kept as a control. Both samples were left stoppered from the air, but exposed to light. After seven days, the material in the test tube containing the complex had polymerized and was completely solid while the control sample was still as fluid as it had been originally. v

The above procedure was repeated using methyl methacrylate. After five days the sample with the complex had polymerized and was solid while the control was still fluid.

I claim:

1. A diiron hexacarbonyl complex of benzo(c)cinnoline which has the following structural formula;

wherein R and R are hydrogen, methyl or halogen.

2. The complex of Claim 1 in which R and R are hydrogen.

3. The complex of Claim 1 in which R and R are chlorine.

References Cited Edgell et al., J. Am. Chem. Soc., vol. 87, pp. 3080-88 (1965).

Edgell et al., J. Am. Chem. Soc., vol. 88, pp. 4839-43 (1966).

Porter et al., J. Am. Chem. Soc., vol. 87, pp. 1628-30 (1965).

Yang, Dissertation Abstr., vol. 26, p. 1944 (1965).

Dekker et al., Chem. Comm, 1967, pp. 1243-44 (Dec. 6, 1967). I

HARRY I. MOATZ, Primary Examiner U.S. Cl. X.R.

4463; 252386; 260 C, 89.5 A, 93.5 C 

